Holographic rear window stoplight

Abstract

An improved holographic rear window stoplight is provided and includes a hologram member laminated to the rear window surface. Single or multiple hologram layers may be provided. The hologram layers can have a diffraction grating developed in a position relative to the other diffraction grating to provide a folded reflection of light from a source of light of an appropriate wavelength band to indicate a stoplight from a predetermined angle. Alternatively predetermined indicia can be selectively displayed in either a single or multiple layer configuration. The reflection hologram member is transparent when not in use to all observers and remains transparent to the driver even when in use, and thereby prevents any blocking of his field of view.

What is claimed is: 
     
       1. An improved rear stoplight assembly capable of being mounted in the field of view of the rear view window of a vehicle without obscuring the vision of the driver, comprising: a hologram member capable of being positioned adjacent the rear window;   a source of light of an appropriate wavelength band, characteristic of a stoplight color, capable of being directed to the hologram member and positioned to prevent any obscuring of the vision of the driver, the hologram member having a holographic image with a characteristic of responding to the relative angle of impact of the source of light to direct that light to the rear of the vehicle whereby the hologram member is substantially transparent to the driver while providing a stoplight light effect when illuminated by the source of light, wherein said source of light provides projected directional light and the hologram member is capable of reflecting the light in a range of approximately 60° to 120° to a position substantially horizontal to the support surface of the vehicle;   means for activating the source of light; and   a second reflection holographic image on said hologram member, each holographic image having a series of parallel finges, the respective orientation of the fringes of the first image directing the light from said light source to the second image and then rearward at a position approximately parallel to the support surface of the vehicle whereby exterior incident light will not be reflected forward through the hologram member in to the line of sight of the driver as he looks through his rearview mirror.   
     
     
       2. The invention of claim 1 further including a protective exterior coating on the hologram member to provide abrasion resistance. 
     
     
       3. The invention of claim 1 wherein the hologram member includes a tansparent flexible substrate suitable for lamination to a rear window surface and at least a double layer laminated film bonded to the substrate for providing the hologram member. 
     
     
       4. The invention of claim 1 wherein the source of light is coupled to an edge of the hologram member. 
     
     
       5. The invention of claim 1 wherein the source of light is displaced from the hologram member and a fiber optic link couples the light to an edge of the hologram member. 
     
     
       6. The invention of claim 1 further including a support member for contacting the rearview window wherein the hologram member is mounted on the rearview window, the hologram member extending into the support member and coupling with the source of light adjacent an edge of the hologram member. 
     
     
       7. The invention of claim 1 further including a second holographic image on the hologram member that can be activated to provide indicia, such as a caution. 
     
     
       8. The invention of claim 1 wherein the hologram member has a pair of holographic layers. 
     
     
       9. The invention of claim 1 further including means for providing a visual indicator to the rear of the vehicle other than a stoplight effect. 
     
     
       10. In a vehicle having a rear window that is required to have a stoplight mounted above a certain rear portion of the vehicle and capable of being positioned within the space defining the line of sight of the driver through his rear view mirror, the improvement comprising: a hologram member having a holographic image mounted on the rear window;   a source of light, of an appropriate wavelength band to indicate a stoplight, directed at the hologram, the holographic image having a characteristic to respond to the relative angle of impact of the source of light and to direct the light to the rear of the vehicle while permitting other light impacting the hologram from another direction within the angle of view of the rearview mirror to pass to the driver whereby the hologram member is substantially transparent to the driver while providing a stoplight light from the source of light when activated; and   means for activating the light source upon braking of the vehicle wherein the source of light is mounted with the rear deck of the vehicle; and   a second reflection holographic image on the hologram member, each holographic image having a series of parallel fringes, the respective orientation of the fringes of the first image is capable of directing the light from the light source to the second image and then rearward at a position approximately parallel to the support surface of the vehicle whereby exterior incident light will not be reflected forward through the hologram member into the line of sight of the driver as he looks through his rearview mirror.   
     
     
       11. The invention of claim 10 further including a protective exterior coating on the hologram member to provide abrasion resistance. 
     
     
       12. The invention of claim 10 wherein the hologram member includes a transparent flexible substrate suitable for lamination to a rear window surface and at least a double holographic layer laminated film bonded to the substrate for providing the hologram member. 
     
     
       13. The invention of claim 10 wherein the source of light is coupled to an edge of the hologram and the light travels through the hologram before being directed out of the hologram by the holographic image. 
     
     
       14. An improved rear window for a vehicle comprising: a transparent rear window substrate of a configuration for mounting within the rear window aperture of a vehicle having a hologram member laminated to a surface of the substrate, the hologram member having an image configuration to direct a bandwidth of light, characteristic of the color of a stoplight, to the rear of the vehicle when impacted with that light at a predetermined angle, whereby the hologram member is substantially transparent when viewed from the position of the driver of the vehicle, such position of the driver being at other than the predetermined angle, that will reflect stoplight coloration to provide a stoplight effect; and   a second holographic image on the hologram member, each holographic image having a series of parallel fringes, the respective orientation of the fringes of the first image directing the light from the light source to the second image and then rearward at a position approximately parallel to the support surface of the vehicle whereby exterior incident light will not be reflected forward through the hologram member into the line of sight of the driver as he looks through his rearview mirror.   
     
     
       15. The invention of claim 14 further including means for coupling the light into an edge of the hologram so that it travels through the hologram in one direction before being directed out of the hologram in a second direction by the holographic image. 
     
     
       16. The invention of claim 15 wherein the hologram member includes a transparent flexible substrate suitable for lamination to a rear window surface and at least a double layer laminated film bonded to the substrate for providing the hologram member. 
     
     
       17. The invention of claim 14 further including a protective exterior coating on the hologram member to provide abrasion resistance. 
     
     
       18. An improved rear stoplight assembly capable of being mounted within the field of view of the rearview window of a vehicle without obscuring the vision of the driver, comprising: means for providing a stoplight within the rearview window including a substantially transparent and colorless stoplight member mounted adjacent the rear window and within the rearview vision of the driver;   means for activating the stoplight member to produce a light directed to the rear of the vehicle of a characteristic wavelength band for a stoplight that is substantially visible only to an observer behind the vehicle and not to the driver, the driver's field of view extending through the stoplight member regardless of its activation; and   a holographic image of said substantially transparent and colorless stoplight member and a reflection holographic image on said means for providing a stoplight member both having a series of parallel fringes, the respective orientation of the fringes of the image of said stoplight member directing the light from the means for activating the stoplight member to produce a light to said reflection holographic image and then rearward at a position approximately parallel to said rearview window of the vehicle whereby exterior incident light will not be reflected forward through said stoplight member into the line of sight of the driver as he looks through his rearview mirror.   
     
     
       19. The invention of claim 18 wherein the transparent stoplight member includes a hologram member with diffraction gratings developed in a holographic layer. 
     
     
       20. The invention of claim 19 wherein the means for activating the stoplight member includes a source of light of an appropriate wavelength band and incidence of impact on the hologram diffraction gratings. 
     
     
       21. The invention of claim 20 wherein the source of light is positioned to direct light along the length of the holographic layer before contacting the diffraction gratings for subsequent direction of the light out of the hologram member. 
     
     
       22. A combined rear stoplight display assembly and illuminated sign member capable of being mounted within the field of view of the rearview window of a vehicle without obscuring the vision of the driver, comprising: means for providing a stoplight within the rearview window including a substantially transparent display member mounted adjacent the rear window and within the rearview vision of the driver;   means for activating the display member to produce a light directed to the rear of the vehicle of a characteristic wavelength band for a stoplight, that is substantially visible only to an observer behind the vehicle and not to the driver;   reflection holographic image on said means for providing a stoplight, a holographic image of said substantially transparent display member and a reflection holographic image on said means for protecting a stoplight member both having a series of parallel fringes, the respective orientation of the fringes of the image of said display member directing the light from the means for activating the display member to produce a light to said reflection holographic image and then rearward at a position approximately parallel to said rearview window of the vehicle whereby exterior incident light will not be reflected forward through said stoplight member into the line of sight of the driver as he looks through his rearview mirror; and   means for activating the generation of predetermined indicia on the display member, that is substantially visible only to an observer behind the vehicle, the driver's field of view extending through the display member regardless of its activation as either a stoplight or for displaying indicia.   
     
     
       23. The invention of claim 22 wherein the transparent display member includes a hologram member with diffraction gratings developed in a holographic layer. 
     
     
       24. The invention of claim 23 wherein the means for activating the display member includes a source of light of an appropriate wavelength band and incidence of impact on the hologram diffraction gratings. 
     
     
       25. The invention of claim 24 wherein the source of light is positioned to direct light along the length of the holographic layer before contacting the diffraction gratings for subsequent direction of the light out of the hologram member. 
     
     
       26. The invention of claim 24 wherein the diffraction gratings for the predetermined indicia have been constructed to compensate for the curvature of the rearview window. 
     
     
       27. The invention of claim 24 wherein the diffraction gratings are activated by a first light of a predetermined wavelength band to provide a stoplight effect and a second light of a different predetermined wavelength band to display the predetermined indicia.